Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Sample handling of gastric tissue and O-glycan alterations in paired gastric cancer and non-tumorigenic tissues.

Author(s): Adamczyk B, Jin C, Polom K, Muñoz P, Rojas-Macias MA, Zeeberg D, Borén M, Roviello F, Karlsson NG

Publication: Sci Rep, 2018, Vol. 8, Page 242

PubMed ID: 29321476 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study compared the effects of preservation by snap-freezing and heat stabilization on the recovery of glycans from tumor and normal adjacent gastric tissue. Two tumor and two normal adjacent gastric tissue specimens were collected from each of six patients undergoing gastric cancer surgery (3 male, 3 female; 67–91 years old, median age 85), immediately snap-frozen in liquid nitrogen or heated at 95°C in the Stabilizor T1 instrument using automated settings for fresh tissue, and then stored at −80°C until analysis. Specimens (50 mg) were placed in homogenization tubes, loaded with zirconium oxide beads (3 mm), and homogenized in a solubilization buffer containing a protease inhibitor cocktail. Protein extraction was performed overnight followed by incubation with 25 mM IAA for 40 min at RT in the dark. The extracts were centrifuged for 20 min at 13,200 rpm and the supernatants were stored at −20°C until analysis of glycans by LC-MS/MS.

   Summary of Findings:

   There were no significant differences in LC-MS/MS glycan spectral intensities between specimens preserved by snap-freezing and those preserved by heat stabilization for either tumor (R²=0.991) or normal adjacent tissue (R²=0.953). Further, structural features of O-glycans in protein extracts from snap-frozen and heat stabilized specimens did not differ, suggesting similar levels of degradation between the two preservation methods. However, differences between tumor and normal adjacent specimens were observed in 9 of the 83 O-glycan structures examined and in 1 of the 17 calculated structural features. Glycans isolated from tumor tissues demonstrated an increase in sialylation compared to normal adjacent tissue (P=0.1) and a decrease in LacdiNAc and blood group H epitopes (P=0.06 and P=0.10, respectively) with the most significant differences observed for the LacdiNAc epitope (P=0.013 for AB groups in snap frozen specimens and P=0.015 for CD groups in heat stabilized specimens).

   Biospecimens

   • Tissue - Stomach

   Preservative Types

   • Other Preservative
   • Frozen

   Diagnoses:

   • Neoplastic - Carcinoma
   • Neoplastic - Normal Adjacent

   Platform:

   Analyte	Technology Platform
   Carbohydrate	LC-MS or LC-MS/MS

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Type of fixation/preservation	Snap frozen Heat stabilization

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